Touch pad with flexible substrate

ABSTRACT

A touch sensor device is provided that uses a flexible circuit substrate to provide an improved input device. Specifically, the present invention uses a touch sensor controller affixed to the flexible circuit substrate, which is coupled to a sensor component to provide a flexible, reliable and cost effective touch sensor suitable for a wide variety of applications. In one embodiment the touch sensor uses a flexible circuit substrate that provides relatively high temperature resistance. This allows the touch sensor controller to be affixed using reliable techniques, such as various types of soldering. The sensor component can comprise a relatively low-temperature-resistant substrate that can provide a cost effective solution. Taken together, this embodiment of the touch sensor provides reliability and flexibility at relatively low cost.

CROSS-REFERENCES TO RELATED APPLICATIONS

This is a continuation of U.S. application Ser. No. 13/675,312, filedNov. 13, 2012, which is a continuation of U.S. Pat. No. 8,330,742,issued Dec. 11, 2012, which is a continuation of U.S. Pat. No.8,085,250, issued Dec. 27, 2011, which is a continuation of U.S. Pat.No. 7,439,962, issued Oct. 21, 2008, all of which are incorporatedherein by reference.

FIELD OF THE INVENTION

This invention generally relates to electronic devices, and morespecifically relates to touch sensor devices.

BACKGROUND OF THE INVENTION

Touch sensor devices (also commonly called touch pads) are widely usedin a variety of electronic systems. A touch sensor device is typically asensitive surface that uses capacitive, resistive, inductive, optical,acoustic or other technology to determine the presence, location and ormotion of one or more fingers, styli, and/or other objects. The touchsensor device, together with a finger or other object provides an inputto the electronic system. For example, touch sensor devices are used asinput devices for computers, such as notebook computers.

Touch sensor devices are also used in smaller devices, such as personaldigital assistants (PDAs) and communication devices such as wirelesstelephones and text messaging devices. Increasingly, touch sensordevices are used in multimedia devices, such as CD, DVD, MP3 or othermedia players. Many electronic devices include a user interface, or UI,and an input device for interacting with the UI. A typical UI includes ascreen for displaying graphical and/or textual elements. The increasinguse of this type of UI has led to a rising demand for touch sensordevices as pointing devices. In these applications the touch sensordevice can function as a cursor control device, selection device,scrolling device, character/handwriting input device, menu navigationdevice, gaming input device, button input device, keyboard and/or otherinput device.

Past designs of touch pads have had several notable limitations. Onelimitation has been the relative inflexibility of some designs toconform to the limited spaces available in some applications. Forexample, some designs have required large and inflexible circuit boardsthat prevented the touch pad from being used in small, low profile, orirregular spaces. One other notable limitation has been the cost of someprevious designs. For example, some designs have relied exclusively onhigh cost materials for the substrates in the touch pads. The extensiveuse of these materials can be cost prohibitive for some applications.Finally, some previous designs have had limited long term reliability.

Therefore what is needed is an improved touch sensor device design thatprovides space flexibility and reliability without excessive devicecost.

BRIEF SUMMARY OF THE INVENTION

The present invention provides a touch sensor device that uses aflexible circuit substrate to provide an improved input device.Specifically, the present invention uses a touch sensor controlleraffixed to the flexible circuit substrate, which is coupled to a sensorcomponent to provide a flexible, reliable and cost effective touchsensor suitable for a wide variety of applications. For example, thetouch sensor device may be mounted either above or below a flat orcurved rigid substrate.

In one embodiment the touch sensor uses a flexible circuit substratethat provides relatively high temperature resistance. This allows thetouch sensor controller to be affixed using reliable techniques, such asvarious types of thermal bonding. The sensor component can comprise arelatively low-temperature-resistant flexible substrate that can providea cost effective solution. Taken together, this embodiment of the touchsensor provides reliability and flexibility at relatively low cost.

The sensor component can be electrically coupled to the flexible circuitsubstrate using a variety of suitable techniques. For example, in somecapacitive touch sensors capacitive coupling can be used to provideconnection between the flexible circuit substrate and the sensorcomponent. In other embodiments ohmic connections can be providedthrough the use of solder, conductive adhesive, anisotropic conductivefilm, ultrasonic welding, or other structures suitable for thesubstrates and their pads.

In another embodiment the flexible circuit substrate of the touch sensorincludes an integral flexible tail portion. The tail portion comprises arelatively narrow strip of flexible circuit substrate with at least onecontact at its end for connection to an electronic system.

BRIEF DESCRIPTION OF DRAWINGS

The preferred exemplary embodiment of the present invention willhereinafter be described in conjunction with the appended drawings,where like designations denote like elements, and:

FIG. 1 is a block diagram of an exemplary system that includes a touchsensor device in accordance with an embodiment of the invention;

FIGS. 2 and 3 are schematic views of a first embodiment of a touchsensor device;

FIGS. 4 and 5 are schematic views of a second embodiment of a touchsensor device;

FIG. 6 is a schematic view of a flexible circuit substrate in accordancewith a third embodiment; and

FIG. 7 is a schematic view of a sensor component in accordance with afourth embodiment.

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description is merely exemplary in nature and isnot intended to limit the invention or the application and uses of theinvention. Furthermore, there is no intention to be bound by anyexpressed or implied theory presented in the preceding technical field,background, brief summary or the following detailed description.

According to various exemplary embodiments, a touch sensor device isprovided that uses a flexible circuit substrate to provide an improvedinput device. Specifically, the present invention uses a touch sensorcontroller affixed to the flexible circuit substrate, which is coupledto a sensor component to provide a flexible, reliable and cost effectivetouch sensor suitable for a wide variety of applications. In oneembodiment the touch sensor uses a flexible circuit substrate thatprovides relatively high temperature resistance. This allows the touchsensor controller to be affixed using reliable thermal techniques, suchas various types of soldering, thermal bonding, thermally activatedadhesives and ultrasonic welding. Unfortunately, flexible circuitsubstrate materials capable of withstanding thermal bonding techniquesare typically more expensive than those materials which cannot.Advantageously, the sensor component can comprise a relativelylow-temperature-resistant substrate. Taken together, this embodiment ofthe touch sensor provides reliability and flexibility at relatively lowcost.

Although the various embodiments described herein are referred to as“touch sensors” or “touch pads”, these terms as used herein are intendedto encompass not only conventional touch sensor devices, but also abroad range of equivalent devices that are capable of detecting theposition of a one or more fingers, pointers, styli and/or other objects.Such devices may include, without limitation, touch screens, touch pads,touch tablets, biometric authentication devices, handwriting orcharacter recognition devices, and the like. Similarly, the terms“position” or “object position” as used herein are intended to broadlyencompass absolute and relative positional information, and also othertypes of spatial-domain information such as velocity, acceleration, andthe like, including measurement of motion in one or more directions.Various forms of positional information may also include time historycomponents, as in the case of gesture recognition and the like.Accordingly, touch sensors appropriately detect more than the merepresence or absence of an object and may encompass a broad range ofequivalents.

Turning now to the drawing figures, FIG. 1 is a block diagram of anexemplary electronic system 100 that is coupled to a touch sensor device116. Electronic system 100 is meant to represent any type of personalcomputer, portable computer, workstation, personal digital assistant,video game player, telephone, media player or other device capable ofaccepting input from a user and of processing information. Accordingly,the various embodiments of system 100 may include any type of processor,memory or display. Additionally, the elements of system 100 maycommunicate via a bus, network or other interconnection. The touchsensor device 116 can be connected to the system 100 through any type ofinterface or connection, including PS/2, Universal Serial Bus (USB),wireless, or other type of connection to list several non-limitingexamples.

Touch sensor device 116 is sensitive to the position of a stylus 114,finger and/or other object within a sensing region 118. “Sensing region”118 as used herein is intended to broadly encompass any space above,around, in and/or near the touch sensor device 116 wherein the sensor ofthe touchpad is able to detect a position of the object. In aconventional embodiment, sensing region 118 extends from the surface ofthe sensor in one or more directions for a distance into space untilsignal-to-noise ratios prevent object detection. This distance may be onthe order of centimeters or more, and may vary significantly with thetype of position sensing technology used and the accuracy desired.Accordingly, the planarity, size, shape and exact locations of theparticular sensing regions 116 will vary widely from embodiment toembodiment.

In operation, touch sensor 116 suitably detects a position of stylus 114or other object within sensing region 118, and provides electrical orelectronic indicia of the position to the electronic system 100. Thesystem 100 appropriately processes the indicia to accept inputs from theuser, to move a cursor or other object on a display, or for any otherpurpose.

The touch sensor 116 can use a variety of techniques for detecting thepresence of an object. As several non-limiting examples, the touchsensor 116 can use capacitive, resistive, inductive, or opticaltechniques. In a capacitive implementation of a touch sensor a voltageis typically applied to create an electric field across the sensingsurface. A capacitive touch sensor 116 would then detect the position ofan object by detecting changes in capacitance caused by the object.Likewise, in a common resistive implementation a flexible top layer anda bottom layer are separated by insulating elements. Pressing theflexible top layer creates electrical contact between the top layer andbottom layer. The resistive touch sensor 116 would then detect theposition of the object by detecting changes in resistance caused by thepresence of the object. In an inductive implementation, the sensor mightpick up loop currents induced by a resonating coil or pair of coils, anduse some combination of the magnitude, phase and frequency to determinedistance, orientation or position. In all of these cases the touchsensor 116 detects the presence of the object and delivers positioninformation to the system 100.

In the illustrated embodiment the touch sensor 116 is proximate buttons120. The buttons 120 can be implemented to provide additional inputfunctionality to the touch sensor 116. For example, the buttons 120 canbe used to facilitate selection of items using the touch sensor 116. Ofcourse, this is just one example of how additional input functionalitycan be added to the touch sensor 116, and in other implementations thetouch sensor 116 could include additional input devices. Conversely, thetouch sensor 116 can be implemented with no additional input devices.

In this application the device to which the touch sensor connects to orcommunicates with will generally be referred to as an “electronicsystem”. The electronic system could thus comprise any type of device inwhich a touch sensor can be implemented or coupled to. Furthermore, itshould be noted that the touch sensor could be implemented as part ofthe electronic system, or coupled to the electronic system using anysuitable technique. As non-limiting examples the electronic system couldthus comprise any type of computing device, media player, communicationdevice, or another input device (such as another touch sensor orkeypad). In some cases the electronic system is itself a peripheral to alarger system. For example, the electronic system could be a data inputor output device, such as a remote control or display device, thatcommunicates with a computer or media system (e.g., remote control fortelevision) using a suitable wireless technique. It should also be notedthat the various elements (processor, memory, etc.) of the electronicdevice could be implemented as part of the electronic system, as part ofthe touch sensor, or as a combination thereof Additionally, theelectronic system could be a host or a slave to the touch sensor.

According to various exemplary embodiments, a touch sensor device isprovided that uses a flexible circuit substrate to provide an improvedinput device. In one embodiment a touch sensor controller is affixed tothe flexible circuit substrate, which is coupled to a sensor componentto provide a flexible, reliable and cost effective touch sensor suitablefor a wide variety of applications. Additionally, the touch sensor inone embodiment uses a flexible circuit substrate that providesrelatively high temperature resistance. This allows the touch sensorcontroller to be affixed using reliable techniques, such as varioustypes of thermal bonding, without negatively impacting the dimensionalstability of the substrate. The sensor component can comprise arelatively low-temperature-resistant substrate with at least one sensingelement that can provide a cost effective solution. Taken together, thisembodiment of the touch sensor provides reliability, flexibility andrelatively low cost.

Turning now to FIGS. 2 and 3, a first embodiment of a touch sensordevice 200 is illustrated. The touch sensor device 200 includes aflexible circuit substrate 202 and a sensor component 204. FIG. 2illustrates the flexible circuit substrate 202 and sensor component 204separately, while FIG. 3 illustrates the substrates coupled together asthey may be in a completed touch sensor device.

In the illustrated embodiment, the flexible circuit substrate 202includes a touch sensor controller 206, the touch sensor controller 206coupled to a plurality of pads 208 through a plurality of conductors210. The sensor component 204 includes a substrate 205 and a pluralityof columnar sensing elements 214 for detecting an object proximate tothe sensing elements 214. Each of the plurality of sensing elements 214is coupled to a pad 212. When assembled together and in operation, thetouch sensor device 200 detects objects that are proximate to thesensing elements 214, and using the pads 208 and 212, conductors 210,and controller 206 processes and communicates information regarding theposition and/or motion of the proximate object.

While the embodiment illustrated in FIGS. 2 and 3 shows the sensingelements 214 arranged as substantially planar and in columns, this isjust one example of how the sensing elements 214 could be arranged. Forexample, the sensing elements 214 could have concave or convex features,be simple polygons or have complex shapes, or be arranged in circles orother suitable non-rectangular shapes. The configuration, shape andnumber of sensing elements 214 would typically be determined by thesensing requirements of the specific application, and the type ofsensing technology being used. For example, typically the shapes ofsensing elements 214 would differ between touch sensors that usecapacitive sensing and those that use inductive or resistive sensing.Some sensing technologies, such as some capacitive and resistive sensingtechnologies, can be enabled with only one single sensing element 214 orone single pad 208. Similarly, flexible circuit substrate 202 and sensorcomponent 204 also differ in shape, size and arrangement from thoseshown, depending on the specific application.

The sensing elements 214 on the sensor component 204 and the controller206 on the flexible circuit substrate 202 are coupled together throughthe plurality of pads 208 and the plurality of pads 212. The pads 208and 212 can be any suitable type of connection structure. Furthermore,any suitable type of connection mechanism can be used to implement theelectrical connection between pads 208 and 212. For example, the pads208 and 212 can comprise conductive electrodes that are electricallyconnected together with conductive adhesive, conductive foam or otherconductive media. In other cases the pads 208 and 212 could be coupledtogether capacitively, or held together using non-conductive adhesive.Other examples include inductive or significantly resistive coupling. Itshould also be noted that while the pads 208 and 212 are illustrated asrelatively larger than the conductors 210, this is not required. In somecases the pads 208 could just comprise specific portion of theconductors 210 designed to provide connection between the layers. Itshould be noted that in some embodiments more than one layer ofconductors would be formed on the flexible circuit substrate 202, withthose layers separated by one or more dielectric material layers.

The sensing elements 214 and conductors 210, or any other conductiveelements in the touch sensor device, can comprise any suitable type(s)of conductive material, such as conductive ink. The sensing elements 214and conductors 210 can also be formed on the sensor component 204 usingany suitable process. One example is conductive ink printing, such asscreen, ink jet, or offset/transfer printing. In other examples, thesensing elements 214 and conductors 210 can be metallic conductorspatterned on flexible circuit substrate 202 by deposition, etching,molding, stamping, and/or other patterning methods. The processes listedabove are only examples of possible manufacturing methods forconstructing either substrate and should not be considered as limitingin scope.

It should also be noted that in some embodiments it is desirable for thesensor component 204 and flexible circuit substrate 202 to havedifferent minimum conductor pitches. For example, printed inks typicallyhave larger pitch than etched conductors. This is due to the single stepmasking process using a screen or transfer mold, which is inexpensive,but currently difficult to hold vertical and horizontal tolerances(using mechanical alignment). Conversely, photo mask and etchedprocesses have more steps and consumed materials, but the photo maskresist is very well controlled in thickness, and the exposure step istypically optically aligned each time. Stamped conductors can hold quitetight pitches, but are less common, and not easily aligned in multiplelayers. Screen printing is usually limited by the thickness of thescreen that can be handled, while etched or plated electrodes arelimited by over etching or plating due to the thickness of the etched orplated electrode or resist. For all of these reasons it may be desirablefor the sensor component 204 and flexible circuit substrate 202 to havedifferent minimum conductor pitches.

The touch sensor controller 206 is coupled to the plurality of pads 208through a plurality of conductors 210. In general, the touch sensorcontroller 206 comprises one or more integrated circuits that receiveselectrical signals from the sensing elements 214 and communicates withthe electronic system. The touch sensor controller 206 can also performa variety of processes on the signals received from the sensing elements214 to implement the touch sensor. For example, the touch sensorcontroller 206 can select or connect individual sensor electrodes,detect presence/proximity and report a position when a threshold isreached, and/or interpret and wait for a validtap/stroke/character/button sequence before reporting it to the host, orindicating it to the user. In other embodiments the touch sensorcontroller 206 passes the signals to the electronic system and themajority of the processing is performed on other processors such asthose on the electronic system. In this case, the touch sensorcontroller 206 receives electrical signals from the sensing elements 214and facilitates object sensing by communicating with the electronicsystem.

In certain embodiments, one or more active or non-active components mayinterface with touch sensor device 200. An example of an activecomponent would be a button and an example of a non-active componentwould be a light-emitting diode (LED) or power supply. These componentsmay be part of an electronic system and connected to the flexiblecircuit substrate 202 or independent of flexible circuit substrate 202.

As discussed above, the touch sensor device 200 uses a flexible circuitsubstrate to provide an improved input device. Specifically, touchsensor controller 206 is affixed to the flexible circuit substrate,which is coupled to a sensor component to provide a flexible, reliableand cost effective touch sensor suitable for a wide variety ofapplications. The touch sensor controller 206 can be affixed to theflexible circuit substrate 202 using a variety of techniques. Tofacilitate affixing the touch sensor controller 206, the flexiblecircuit substrate 202 would typically include a plurality of landingpads or other suitable coupling structures for receiving the touchsensor controller 206. The type of structures used would depend on thepackaging of the controller 206. In many cases the structures would beformed using the same processing that forms the conductors 210 and pads208.

In one embodiment the touch sensor uses a flexible circuit substratematerial that provides relatively high temperature resistance. Thisallows the touch sensor controller 206 to be affixed using thermalbonding processes that involve the use of heat to affix the controller206. For example, the touch sensor controller can be affixed to theflexible circuit substrate 202 using a thermal bonding process such assoldering, ultrasonic welding, thermally activated adhesive or thermalcompression bonding. These and other thermal bonding processes typicallyhave the advantage of higher reliability, stability, lower cost, oreasier manufacturability when compared to typical lower-temperatureprocesses such as conductive adhesive.

In general a material has heat resistance to a temperature if it can besubjected to that temperature for a length of time without sufferingsignificant degradation, such as a significant loss of dimensionalstability. The amount of heat resistance desired for the flexiblecircuit substrate 202 would depend upon the thermal bonding process usedand the heat required for that process. For example, to reliably bond acontroller to a flexible circuit substrate using traditional solderreflow, the substrate may need to have temperature resistance to 150° C.

A variety of different types of materials can be used for the flexiblecircuit substrate 202. For example, a condensate film or thermosetmaterial such as polyimide has a relatively high level of temperatureresistance. Other temperature-resistant materials that can be used for aflexible circuit substrate 202 include epoxy resins and liquid crystalpolymer films. Of course, these are just examples of the types ofmaterials that can be used for the flexible circuit substrate 202.

The use of flexible circuit substrate 202 in a touch sensor device 200also provides flexibility in shaping the device. For example, a flexiblecircuit substrate 202 can facilitate folding, bending or otherwisemanipulating the touch sensor to conform to a limited space. This canfacilitate the use of the touch sensor device 200 in applications wherespace is at a premium and where the shape of the overall device requiresflexibility in the shape of the circuit substrate. Other potentialreasons for folding or bending the substrate 202 include folding toprovide a shield for the substrate, to reduce cost by improvingpanelization, or to connect two different parts of the substratetogether in a single layer patterning process.

As described above, in one embodiment the sensor component 204 cancomprise a relatively low-temperature-resistant substrate 205 that canprovide a cost effective solution. In this embodiment the sensorcomponent 204 has a temperature resistance that is less than (or equalto) the flexible circuit substrate 202. The relatively low temperatureresistance of the sensor component 204 can provide significant costadvantages when compared to making the entire touch sensor usinghigh-temperature-resistant material. Thus, taken together, the use of arelatively high-temperature-resistant flexible circuit substrate with arelatively low-temperature-resistant sensor substrate providesreliability, flexibility and relatively low cost. Additionally, otherpotential differences between the flexible circuit substrate and thesensor layer substrate include thickness, which controls the bendingradius. Similarly, the flexible circuit substrate could also bepatterned in a more expensive way to connect to the controller, while aless expensive method is used for the sensor substrate. Alternatively, asimilar patterning method, but of a completely different (e.g.,transparent) conductor such as indium tin oxide (ITO) could be used forthe sensor.

A variety of different materials can be used for the sensor component204. For example, a thermoplastic material such as polyethyleneterephthalate (PET) can be used. These materials provide reduced heatresistance when compared to common thermoset or condensate films, but ata significantly reduced cost. This is often due to the extra cost of anexpensive process such as extrusion or molding compared to a “blow”plastic film process. For example, some thermoplastic materials have aheat resistance of 120° C. or less. Of course, this is just one exampleof the type of materials that can be used for the sensor component 204.

In some applications it is desirable to use a flexible material for thesensor component 204. The use of a flexible material for the sensorcomponent 204 provides flexibility in shaping the device. For example,the use a flexible material can facilitate shaping of the touch sensorto provide a curved sensing surface. Examples of flexible materials thatcan be use for sensor component 204 include vinyl, PET, polystyrene(PS), polyvinylchloride (PVC), and polycarbonate.

Turning now to FIGS. 4 and 5, a second embodiment of a touch sensordevice 400 is illustrated. The touch sensor device 400 includes aflexible circuit substrate 402 and a sensor component 403. The sensorcomponent 403 includes first sensor substrate 404 and a second sensorsubstrate 406. FIG. 4 illustrates the flexible circuit substrate 402,first sensor substrate 404 and second sensor substrate 406 separately,while FIG. 5 illustrates the substrates 402, 404 and 406 coupledtogether as they would be in a completed touch sensor device. In thisembodiment the two sensor substrates 404 and 406 each provide objectposition detection in a different direction. Specifically, each sensorsubstrate includes a set of sensing elements arranged in a different,nonparallel (e.g., orthogonal) direction. Taken together, the two sensorsubstrates 404 and 406 provide the ability to detect and preciselylocate a proximate object in two dimensions. Alternatively, the twosensor substrates 404 and 406 can also enable sensing technologies thatrequire non-coplanar sensing elements, such as some resistive sensingtechnologies. To facilitate the use of two sensor substrates 404 and406, the flexible circuit substrate includes a first plurality of pads408 and a second plurality of pads 410, each of the pluralities of padscoupled to the controller through pluralities of conductors.

Like the first embodiment, this touch sensor device 400 includes a touchsensor controller affixed to the flexible circuit substrate 402, andcoupled to the sensing elements through pluralities of conductors andthe pluralities of pads. When assembled together and in operation, thetouch sensor device 400 detects objects that are proximate to thesensing elements. Using the controller, the touch sensor 400communicates information regarding the position and/or motion of theproximate object to an electronic system (not shown in FIG).

Like the first embodiment, the touch sensor device 400 uses a flexiblecircuit substrate to provide an improved input device. Specifically, thetouch sensor uses a flexible material that provides relatively hightemperature resistance. This allows the touch sensor controller to beaffixed using thermal bonding processes that involve the use of heat.Conversely, the first touch sensor substrate 404 and second touch sensorsubstrate 406 can both or either comprise a relativelylow-temperature-resistant substrate that can provide a cost effectivesolution. The relatively low temperature resistance of the sensorsubstrates 404 and 406 can provide significant cost advantages whencompared to making the entire touch sensor usinghigh-temperature-resistant material. Thus, taken together the use of arelatively high-temperature-resistant flexible circuit substrate with arelatively low-temperature-resistant sensor component providesreliability, flexibility and relatively low cost.

As a variation on this embodiment, instead of using two separate touchsensor substrates 404 and 406, the sensor elements for both directionscan be formed on a single sensor substrate. For example, the sensorelements for both directions can be formed on opposite sides of a singlesensor substrate. In this embodiment, the pads 408 and 410 may belocated on opposite sides of the flexible circuit substrate 402 tofacilitate coupling to the single touch sensor substrate. Alternatively,the sensor elements for both directions can be formed on the same sideof a single sensor substrate, separated by an insulative material. Inthis embodiment, the insulative material between sensor elements ispreferably formed using a process similar to those for forming thesensor elements. All these embodiments can provide two dimensionalsensing while requiring only one sensor substrate, or can be used toenable other sensing technologies. This can further reduce materialcosts at the expense of somewhat increased manufacturing complexity.Other possible variations in these embodiments include folding theflexible circuit substrate. The flexible circuit substrate can also beslit to allow one substrate to pass through another or to increase taillength or have multiple tails. Finally, a variety of other devices couldbe added to the flexible circuit substrate including alignment holes orother features for aiding assembly, lamination, bonding, or finalconnection.

Turning now to FIG. 6, a third embodiment touch sensor device 600 isillustrated. In this embodiment the touch sensor 600 includes a flexiblecircuit substrate 602 and at least one sensor component (not shown inFIG.). This embodiment, like the previous two embodiments uses aflexible circuit substrate with relatively high temperature resistanceto provide an improved input device. When combined with relativelylow-temperature-resistant sensor components the embodiment can providesignificant cost advantages when compared to making the entire touchsensor using high-temperature-resistant material.

In this embodiment, the flexible circuit substrate 602 includes anintegral tail portion 604. The tail portion 604 comprises a relativelynarrow strip of flexible circuit substrate with at least one conductor606 and at least one contact electrode 608 at its end for connection orcommunication to an electronic system. Because the integral tail portion604 is made of a flexible circuit substrate material and is relativelynarrow, the integral tail portion 604 can be shaped, bent, or otherwisemanipulated to provide the connection to the electronic system.Specifically, the integral tail portion 604 can be bonded directly tocontact electrodes of the electronic system, plugged into a suitableconnector on the electronic system, or into a suitable connector that iscoupled to the electronic system. In some embodiments a first stiffenermaterial 610 is added to the end of the integral tail portion 604. Thestiffener material 610 reduces the flexibility in that portion of thesubstrate by relieving strain and thus improves the reliability of theconnection between the connector and the tail portion 604. A variety oftypes of materials can be used as the stiffener 610, including PET,polyimide, polystyrene, and PVC. The addition of the tail portion 604 tothe flexible circuit substrate 600 can thus provide connection to theelectronic system, and can thus further reduce the complexity and costof the overall device. It should be noted that the tail portion 604could be configured in a variety of shapes and structures. It shouldalso be noted that a tail portion can be located on a flexible sensorsubstrate, such as those shown in the first and second embodiments, inaddition to or in place of tail portion 604.

In FIG. 6, a second stiffener 612 is formed under the touch sensorcontroller 614. The stiffener 612 under the touch sensor controller 614can serve to improve the reliability of the connection between the touchsensor controller 614 and the flexible circuit substrate 602. Thestiffener 612 provides strain relief and reduces bending curvature dueto or concentrated by connection to other elements. Additionally, thestiffener 612 may also provide greater flatness or stability formechanical manipulation during assembly or connection. The stiffener 612might also be formed as a fillet of adhesive at an interconnectionbetween a flexible substrate and other connector element of theelectrical system. For example, an acrylic, an epoxy, or UV curedadhesive may be used.

Turning now to FIG. 7, another embodiment of a touch sensor component700 is illustrated. The touch sensor component 700 again includes aplurality of sensing elements 702 for sensing an object proximate to atouch sensor. In this embodiment the touch sensor component 700 alsoincludes a conductive shield 704. The conductive shield 704 is formed onthe sensor component 700 in a location where it will shield sensitiveelements of the touch sensor. For example, when the conductive shield isformed and assembled as illustrated in FIG. 5, the conductive shield 704will prevent unwanted capacitance from affecting the conductors on theflexible circuit substrate. The conductive shield 704 can be activelydriven or grounded through a conductor disposed directly on the flexiblesensor substrate 700 or the corresponding flexible circuit substrate, orthrough any other electrical connection to the corresponding touchsensor device or electronic system. Thus, the conductive shield 704 canincrease the reliability, repeatability and accuracy of the touchsensor.

The conductive shield 704 can be of any size or shape, and formed usinga variety of techniques. Typically, it will be desirable to form theconductive shield 704 with the same processing steps used to form thesensing elements 702. However, different processing steps may bepreferred when the guard is formed with different optical properties(transparent or opaque) than the sensing elements. In particular, when atransparent shield is needed, an inorganic ITO or an organic pedottransparent conductor can be used. Additionally, it may be useful toselect a different location for conductive shield 704, to fold, or tobend the flexible sensor substrate 700. Conductive shield 704 can thusbe better positioned for shielding the flexible circuit substrate, oralternatively be positioned to shield the flexible circuit substrate, oranother element of the system (such as the flexible sensor substrate 700itself). It should be noted that this is just one example of where aconductive shield can be provided to shield the touch sensor device. Inother cases it may be desirable to provide one or more conductiveshield(s) on a flexible circuit substrate, on another substrate in thetouch sensor device, on a part of the touch sensor case or support, oron a part of the electronic system. In all these cases the conductiveshield(s) can be used to improve the performance of the touch sensor byreducing undesirable electromagnetic interference that is either selfinduced or externally generated.

It should be noted that while the sensor layers illustrated in FIGS. 1-7have been substantially rectangular in shape, that a variety of othershapes could be used. For example, a circular shaped touch sensorcomponent can be used to provide a circular sensing surface. The touchsensor can also be non-planar to accommodate curved or angular surfaces.Additionally, the sensing elements themselves can have a variety ofdifferent shapes.

The embodiments of the present invention thus provide a touch sensordevice that uses a flexible circuit substrate to provide an improvedinput device. Specifically, the present invention uses a touch sensorcontroller affixed to the flexible circuit substrate, which is coupledto a sensor component to provide a flexible, reliable and cost effectivetouch sensor suitable for a wide variety of applications. In oneembodiment the touch sensor uses a flexible circuit substrate thatprovides relatively high temperature resistance. This allows the touchsensor controller to be affixed using reliable techniques, such asvarious types of soldering. The sensor component can comprise arelatively low-temperature-resistant substrate that can provide a costeffective solution. Taken together, this embodiment of the touch sensorprovides reliability, flexibility and relatively low cost.

The embodiments and examples set forth herein were presented in order tobest explain the present invention and its particular application and tothereby enable those skilled in the art to make and use the invention.However, those skilled in the art will recognize that the foregoingdescription and examples have been presented for the purposes ofillustration and example only. The description as set forth is notintended to be exhaustive or to limit the invention to the precise formdisclosed. Many modifications and variations are possible in light ofthe above teaching without departing from the spirit of the forthcomingclaims.

What is claimed is:
 1. A sensor device comprising: a flexible circuitsubstrate that is dimensionally stable up to a first temperature; afirst plurality of conductive pads disposed on the flexible circuitsubstrate; a touch controller affixed to the flexible circuit substrateand coupled to the first plurality of conductive pads via a firstplurality of conductors; a flexible sensor substrate that isdimensionally stable up to a second temperature that is lower than thefirst temperature, wherein the flexible sensor substrate is notdimensionally stable at the first temperate; a second plurality ofconductive pads disposed on the flexible sensor substrate, wherein atleast one of the first plurality of conductive pads is coupled to atleast one of the second plurality of conductive pads; and a firstplurality of capacitive sensing elements disposed on the flexible sensorsubstrate and coupled to the second plurality of conductive pads via asecond plurality of conductors.
 2. The sensor device of claim 1, whereinthe flexible sensor substrate is transparent.
 3. The sensor device ofclaim 1, wherein the first temperature is high enough to thermally bondthe touch controller to the flexible circuit substrate withoutdegradation to the flexible circuit substrate.
 4. The sensor device ofclaim 1, further comprising: a second flexible sensor substrate that isdimensionally stable up to the second temperature, wherein the secondflexible sensor substrate is not dimensionally stable at the firsttemperature; a third plurality of conductive pads disposed on the secondflexible sensor substrate, wherein a second at least one of firstplurality of conductive pads is coupled to at least one of the thirdplurality of conductive pads; and a second plurality of capacitivesensing elements disposed on the second flexible sensor substrate andcoupled to the third plurality of conductive pads via a third pluralityof conductors.
 5. The sensor device of claim 1, further comprising asecond plurality of sensing elements disposed on the flexible sensorsubstrate and coupled to the second plurality of conductive pads,wherein the first plurality of capacitive sensing elements and thesecond plurality of sensing elements are disposed on a same side of theflexible sensor substrate.
 6. The sensor device of claim 1, furthercomprising a second plurality of sensing elements disposed on theflexible sensor substrate, wherein the first plurality of capacitivesensing elements and the second plurality of sensing elements aredisposed on different sides of the flexible sensor substrate.
 7. A touchsensor device comprising: a flexible circuit substrate that isdimensionally stable up to a first temperature, the flexible circuitsubstrate comprising a first plurality of conductive pads and a firstplurality of conductors coupled to the first plurality of conductivepads; a touch controller affixed to the flexible circuit substrate andcoupled to the first plurality of conductors; and a sensor componentcomprising: a transparent flexible sensor substrate that isdimensionally stable up to a second temperature that is lower than thefirst temperature; a second plurality of conductive pads disposed on thetransparent flexible sensor substrate, wherein the second plurality ofconductive pads are coupled to the first plurality of conductive pads;and a first plurality of transparent sensing elements disposed on thetransparent flexible sensor substrate and coupled to the secondplurality of conductive pads via a second plurality of conductors. 8.The touch sensor device of claim 7, wherein the sensor component furthercomprises a second transparent flexible sensor substrate that isdimensionally stable up the second temperature and a second plurality oftransparent sensing elements disposed on the second transparent flexiblesensor substrate.
 9. The touch sensor device of claim 7, wherein thesensor component further comprises a second plurality of transparentsensing elements disposed on the transparent flexible sensor substrate,wherein the first plurality of transparent sensing elements and thesecond plurality of sensing elements are disposed a same side of thetransparent flexible sensor substrate.
 10. The touch sensor device ofclaim 7, wherein the sensor component further comprises a secondplurality of transparent sensing elements disposed on the transparentflexible sensor substrate, wherein the first plurality of transparentsensing elements and the second plurality of sensing elements aredisposed on different sides of the transparent flexible sensorsubstrate.
 11. The touch sensor device of claim 7, wherein the touchcontroller is configured to receive electrical signals from at least oneof the first plurality of transparent sensing elements, and wherein thetouch controller is configured to process the electrical signals. 12.The touch sensor device of claim 7, wherein the touch controller isconfigured to receive electrical signals from at least one of the firstplurality of transparent sensing elements, and wherein the touchcontroller is configured to pass the electrical signals to an electronicsystem, wherein the electronic system is configured to process theelectrical signals.
 13. The touch sensor device of claim 7, wherein thefirst temperature is high enough to thermally bond the touch sensorcontroller to the flexible circuit substrate without degradation to theflexible circuit substrate.
 14. The touch sensor device of claim 7,further comprising a conductive shield.
 15. The touch sensor device ofclaim 7, wherein the flexible circuit substrate comprises a tailportion.
 16. The touch sensor device of claim 7, wherein the firstplurality of conductors comprises a first conductor pitch and the secondplurality of conductors comprises a second conductor pitch, wherein thefirst conductor pitch is not equal to the second conductor pitch. 17.The touch sensor device of claim 7, wherein the touch sensor isconfigured to detect a position of at least one object.
 18. The touchsensor device of claim 17, wherein the at least one object comprises atleast one of a finger, pointer and a stylus.
 19. The touch sensor deviceof claim 7, wherein the flexible circuit substrate has a first thicknessand the transparent flexible sensor substrate has a second thicknessdifferent from the first thickness.
 20. An input device comprising: aflexible circuit substrate dimensionally stable up to a firsttemperature, wherein the first temperature allows thermal bonding to theflexible circuit substrate without significant thermally induceddegradation; a first at least one conductive pad disposed on theflexible circuit substrate; a touch controller affixed to the flexiblecircuit substrate and coupled to the first at least one conductive padvia at least one conductor; a transparent sensor substrate that isdimensionally stable up to a second temperature that is lower than thefirst temperature, wherein the transparent sensor substrate is notdimensionally stable above the second temperature; a second at least oneconductive pad disposed on the transparent sensor substrate, wherein thesecond at least one conductive pad is coupled to the first at least oneconductive pad; and at least one conductive sensing element disposed onthe transparent sensor substrate, wherein the second at least oneconductive pad is coupled to the at least one conductive sensingelement, and wherein the touch controller is configured to receiveelectrical signals from the at least one conductive sensing element todetect a position of at least one object in a sensing region of theinput device.
 21. The input device of claim 20, further comprising: asecond transparent sensor substrate that is dimensionally stable up tothe second temperature, wherein the second transparent sensor substrateis not dimensionally stable above the second temperature; and a secondat least one conductive sensing element disposed on the secondtransparent substrate, wherein the at least one conductive sensingelement is along a first direction and the second at least oneconductive sensing element is disposed along a second directiondifferent from the first direction.
 22. The input device of claim 20,further comprising a second at least one conductive sensing elementdisposed on the transparent sensor substrate, wherein the second atleast one conductive sensing element and the at least one conductivesensing element are disposed on a same side of the transparent sensorsubstrate.
 23. The input device of claim 20, further comprising a secondat least one conductive sensing element disposed on the transparentsensor substrate, wherein the second at least one conductive sensingelement and the at least one conductive sensing element are disposed ondifferent sides of the transparent sensor substrate, and wherein thesecond at least one conductive sensing element is disposed orthogonal tothe at least one conductive sensing element.
 24. The input device ofclaim 20, further comprising a display.
 25. A touch screen devicecomprising: a flexible circuit substrate dimensionally stable up to afirst temperature, wherein the first temperature allows thermal bondingto the flexible circuit substrate without significant thermally induceddegradation; a first plurality of conductive pads disposed on theflexible circuit substrate; a first plurality of conductors coupled tothe first plurality of conductive pads; a touch controller affixed tothe flexible circuit substrate and coupled to the first plurality ofconductors; and a sensor component comprising: a flexible transparentsensor substrate that is dimensionally stable up to a second temperaturethat is lower than the first temperature, wherein the flexibletransparent sensor substrate is not dimensionally stable at the firsttemperature; a second plurality of conductive pads coupled the firstplurality of conductive pads and disposed on the flexible transparentsensor substrate; a second plurality of conductors disposed on theflexible transparent sensor substrate and coupled to the secondplurality of conductive pads; a first plurality of transparentcapacitive sensing elements disposed on the flexible transparent sensorsubstrate, wherein the first plurality of transparent capacitive sensingelements are coupled the second plurality of conductors and wherein thefirst plurality of transparent capacitive sensing elements are alignedalong a first direction; and a second plurality of transparentcapacitive sensing elements aligned along a second direction, whereinthe first direction differs from the second direction, wherein the touchcontroller is configured to receive electrical signals from the firstplurality of transparent capacitive sensing elements to determine aposition of an object in a sensing region of the touch screen devicebased on detected changes in capacitance.